Railway frog



Feb. 27, 1962 INVENTOR. WILLIAM A. Me GRA H BY I WififlWMJi Ar-rvs.

S vitch & Manufacturing 60., Carlisie, Pa-, a corp r tron ofPennsylvania Filed Mar. 5, 1959, Ser. No. 797,359 5 (Iiaims. (Cl. 246-368) The present invention relates to railway frogs and the like andmore particularly to such frogs which are formed of work-hardenablemetal such as manganese steel.

A railway frog is a joint, used where two tracks cross one another at anangle, which enables the flanged rail wheels on one rail to crossanother rail of the intersectmg track. The material of which railwayfrogs should be made must possess qualities of toughness, hardness,strength and durability required in withstanding the repeated and severeimpact to which such frogs are subected by the Wheels of passing railwayvehicles. It has been found in practice that various work-hardenablemetals are particularly Well adapted for this purpose, one of the mostpopular being manganese steel.

A conventional practice is to initially cast or other- Wise form thefrog of manganese steel and then, prior to placing it in service, tosubject the frog point and adjacent wing rails with which the rollingstock wheels will be in contact to surface work-hardening to obtain therequired toughness and hardness properties. Surface hardening is usuallyaccomplished by cold working the metal, i.e. plastically deforming themetal at a temperature below that at which spontaneous recrystallizationtakes place. it is well known that such cold Working results m a forcedrecrystallization of the metal grains into finer grain sizes with aresulting enhancement of certain mechanical properties of the metal,especially hardness, toughness, and wear resistance. Common methods ofcold working involve subjecting the metal surface to repeated impactingby hammering, pressing, rolling, shot blasting or the like. As noted,the metal undergoes actual flow or displacement in the process ofhardening. As hardening progresses, the rate of metal flow diminishesuntil a desired degree of hardening is efiected.

As indicated, cold working of the frog point and wing rail surfaces isconventionally carried out in the factory before the frog is placed inservice. Because of the surface metal flow which takes place during workhardening, the usual practice is to initially provide an additionalthickness (cf. /8 inch) of metal on the point and wing surfaces to beWork-hardened. in this way provision is made for bringing the working ortread surfaces of the point and wings to the desired rail level afterthe initial metal excess has been flattened by the cold working process.Some of the excess metal undergoes migratory cold flow to edge areaswhere peening over is possible, necessitating a further grinding of thefrog to give the desired final dimensions.

These and other conventional practices are expensive both in terms ofthe materials and equipment which must be used, and the labor that mustbe expended. Very serious disadvantages inhere in the time consumingnature of the operations.

It is a primary object of this invention to overcome the manydisadvantages of the conventional practices decribed above and others byproviding a frog having wear surfaces which are work-hardenable in situafter the formed but unhardened frog has been placed in service at arail crossing. It is thus an object of this invention to eliminate thenecessity for carrying out work hardening of rail frogs in the factoryand to provide instead for such treatment to take place after the frogis in place in the railroad track.

3,ZZ,%8 Patented Feb. 27, 1962 An ancillary object is to provide a railfrog having wear surfaces which need not be pre-hardened but arework-hardenable in use as a result of passage of the rail vehicle wheelsover the frog wear surfaces.

A further object of the invention is to provide a usehardenable frogwhich, once placed in service, undergoes rapid hardening of its Wearsurfaces during the initial period of use and which need not be furtherground or otherwise shaped to the desired cross-section. Still anotherand allied object is to provide such a use-hardenable frog having wearmembers which retain their overall dimensional uniformity during the inuse Work-hardening process and indefinitely thereafter. Ancillary tothese it is an object to provide such a frog in which the finalcross-sections or shape of the various wear members in use may beaccurately prescribed prior to work hardening of the members.

Other objects and advantages will become apparent upon reading theattached detail description and upon reference to the drawings in which:

FIGURE 1 is a plan view of a railroad track crossing in which a frogembodying the features of the present invention is installed at eachintersection of two rails.

.FIG. 2 is an enlarged fragmentary perspective view of a frog employedin practicing the present invention, showing the frog wear surfacesprior to work hardening.

FIG. 3 is mainly an enlarged plan view, slightly in perspective, showingthe frog point and adjacent wing portions of the frog shown in FIG. 3.

FIG. 4 is a fragmentary, enlarged transverse crosssectional view of theillustrative frog point taken along the line 4-4 of FIG. 3, againshowing the frog wear surfaces prior to work hardening.

While the invention has been described in connection with a preferredembodiment, it will be understood that it is not intended to limit theinvention thereto, but it is intended to cover all modifications andalternative constructions and methods falling within the spirit andscope of the invention as expressed in the appended claims.

Turning now to the drawings there is shown in FIG. 1

a two track crossing including at the junction of each pair ofintersecting rails a frog 10 of the type employed in practicing thepresent invention. For details of the frog structure employed at eachpair of intersecting rails, reference may be had to FIG. 2.

There it will be seen that the general framework of the frog is definedby a pair of ordinary rolled rails bent or forged into the shapes shownso as to form opposing and spaced apart wing rails 12 and 14. As will beseen, the integral wing rails include straight and approximatelyparallel mid-portions 12a, tea, which house the actual rail crossovertherebetween, and end portions 121) and 12c, 14]) and 140, formed toconverge toward the midportion of the frog. The wing rail end portions12b, 14b thus define the toe of the frog.

Short ordinary straight rails 16, 18 are provided in the usual mannerbetween the converging wing rail end portions 12c, 140, thus serving asthe point rails and thereby defining the heel of the frog. Therespective short rails 16, 18 are generally parallel to and spaced fromthe wing rail portions 120, to define therebetween fiangeways 20, 22 foraccommodating the railwheel flanges. As will be observed, the shortrails 16, 18, made of ordinary rail steel, terminate short of the frogmidportion defined between the wing rail portions 12a, 14a.

There is thus defined a generally rectangular opening Within the rails12a, 14a, and the converging ends of the straight rails 16, 18. Disposedin this opening is a central frog member 21, cast in this instance ofmanganese steel and sized and shaped to fit between and form the actualjunction or crossover for the intersecting rails. As will be seen, thefrog member 21 is railbound to the opepsaess posing wing rails 12, 14 bymeans of suitable throughbolts 22.

The structure of the frog member 21 is well illustrated in FIGS. 2 and3. 'It'will be seen that the casting as shown is of integralconstruction and comprises a frog point 24, and two adjacent but spacedopposing frog wing portions 26, 28, respectively. The opposing verticalsurfaces 24a of the frog point and 26a, 28a of the wing portions arespaced suitably to define therebetween a continuation toward the frogpoint of the flangeways 2G, 22. The sharpness angle of the frog point 24is dependent, of course, upon the angle of intersection of the rails.

As shown, the frog member 21 presents generally horizontal, fiat wear ortread surfaces 24h at the frog point and 26b, 28b on the adjacent wingportions for engagement by the wheels of passing rail vehicles.

In carrying out the invention, the rail frog member 21 is provided withmeans facilitating complete work-hardening of its wear surfaces while inuse, is. after the frog has been installed at the rail crossing; yet theoverall dimensional profile of the member is maintained during suchwork-hardening. By such means the basic objectives of the invention areaccomplished, pre-hardening of the frog before track installation is nolonger necessary and once the frog is placed in service no furthergrinding, trimming or other shaping of the frog metal is necessary.

In this instance, each of the wear surfaces in the region of the frogpoint, i.e. surfaces 24b, 26b, 28b, is fluted or provided across itsface with a series of spaced grooves or troughs 30 defining upraisedridge-like por tions 32 of metal which ridges are primarily engaged bythe wheels of moving rail vehicles during the initial period of use ofthe frog. The work-hardenable but initially unhardened wear surfaces ofthe frog, and more particularly the upraised metal ridges 32 thereon,undergo cold flow under the high velocity pounding of the moving 7 railwheels, resulting in work-hardening of the frog Wear surfaces.

Upon particular reference to FIGS. 3 and 4 the nature of the wearsurfaces of the frog employed in practicing the invention will beapparent. As shown, the grooves 30 in the frog point surface 245 are ina V-formation paralleling the side Walls 24a of the point. Thisarrangement orients the grooves and ridges 32 generally in the samedirection as that of the vehicle wheels in passing over the rails. Inthis same manner the grooves 30 provided in the faces 26b, 28b of thefrog wing portions are arranged to run in the direction of motion of thewheels along the rails. It should be understood, of course, that otherorientations of the grooves and ridges may also be employed in keepingwith the spirit and scope of the invention described herein.

As the rail wheels pass over the frog wear surfaces 24b, 26b, 2817, themetal ridges 32 tend to flatten out under the pounding and pressureresulting from the heavy loadings supported by the vehicle wheels andtransmitted to the rails. This flattening out of the metal ridges 32constitutes cold flow of the metal and hardening thereof takes placeincident to the cold flow as discussed above.

An important feature of the invention resides in pro vision in the frogwear surfaces of the grooves 30 adjacent the ridges 32 which groovesprovide low areas into which the upraised metal portions 32 will flowduring the cold working process. This provision of relieved areas in thewear faces of the frog facilitates ready cold flow of the ridge metal 32at a high rate, thus accomplishing hardening of the frog wear surfacesin situ in a minimum of time.

By use of the present invention, it is now possible to be assured thatcold fiow of metal is'directed into the grooves as desired during thework-hardening process, and that metal will not peen'over the topedgesof the fr g wear members and flow into undesirable areas such as thefiangeways as so often occurs with conventional 'rogs now in service. a

It is desirable to initially form the frog wear surfaces such that thetop surfaces of the metal ridges 32 are disposed in a flat planesomewhat higher than the level of the surrounding ordinary rails. Themagnitude of the initial difference in the levels of the ridges 32 andrails may be selected such that cold flow of the ridge metal graduallyreduces the ridges down to the normal or working level of the rails. Thestructure shown and described is particularly advantageous in view ofthe fact that the ridges 32 may be of approximately equal height thusavoiding abrupt peaks in the wear surface contour which might disruptflow of trafiic over the frog or otherwise present maintenance problems.The outline or profile of the frog wear members 24, 26, 28 is generallyfiat both before work hardening and afterward when the ridges 32 have atleast partially flowed into the grooves 33. importantly no overhang ofmetal results in the open flangeway due to fiow of metal that hasnowhere else to go.

The present invention is found to constitute a great boon to therailroads in that the costs of manufacture of railway frogs have beenmaterially reduced and the problem of battering and peening over ofmetal in the area of the frog point into the fiangeways which must bekept clear has been solved.

I claim as my invention:

1. A railroad frog member comprising a point and adjacent wings havingwear surfaces formed of work hardenable but initially 'unhardened metal,the wear surfaces of said point and wings having a series of spacedgrooves therein defining upraised metal portions therebetween positionedfor rolling engagement by the wheels of passing railway vehicles, saidspaced grooves and upraised metal portions being elongated, of uniformcross section throughout their length, and being alined in the directionof travel of the railway vehicle wheels along the rails, and saidupraised metal portions being adapted to plastically flow at leastpartially into said grooves during rolling engagement of the upraisedmetal portions by said vehicle wheels to thereby work harden the wearsurfaces in use.

2. A railroad frog member comprising a frog point having a wear surfaceformed of work hardenable but initially unhardened metal, the wearsurface of said frog point having a series of spaced grooves thereindefining upraised metal portions thcrebetween positioned for rollingengagement by the wheels of passing railway vehicles, said spacedgrooves and upraised metal portions being elongated, of uniform crosssection throughout their length, and being alined in the direction oftravel of the railway vehicle wheels along the rails, and said upraisedmetal portions being adapted to plastically fiow at least partially intosaid grooves during rolling engagement of the upraised metal portions bysaid vehicle wheels to therebywork harden the Wear surface in use,

3. A railroad frog member comprising a point and adjacent wings havingwear surfaces formed of work hardenable but initially unhardened metal,the wear surfaces of said point and wings having spaced relieved areastherein defining rows of upraised metal portions therebetween positionedfor rolling engagement by the wheels of passing railway vehicles, saidspaced grooves and upraised metal portions being elongated, of uniformcross section throughout their length, and being alined in the directionof travel of the railway vehicle wheels along the rails, and saidupraised metal portions being adapted to plastically flow at leastpartially into said relieved areas during rolling engagement of theupraiscd metal portions by said vehicle wheels to thereby work hardenthe wear surfaces in use.

4. The process for producing a surface hardened railroad frog whichcomprises forming a frog member ineluding a frog point and adjacentwings having wear surfaces of work hardenable but initially unhardenedmetal, forming a series of spaced grooves in each of said wear surfacesthus defining upraised metal portions therebetween positioned forengagement by the wheels of passing railway vehicles said spaced groovesand upraised metal portions being elongated, of uniform cross sectionthroughout their length, and being alined in the direction of travel ofthe railway vehicle wheels along the rails, and plastically deformingsaid upraised metal portions at least partially into said spaced groovesto thus work harden the wear surfaces by installing the frog member in arail crossing in use by railway vehicles so that the vehicle wheelsexert pressure upon said upraised portions to thus work harden the wearsurfaces.

5. The process for producing a surface hardened railroad frog whichcomprises forming a frog member including a frog point having a wearsurface of work hardenable but initially unhardened metal, formingspaced relieved areas in said wear surface thus defining rows ofupraised metal portions therebetween positioned for engagement by thewheels of passing railway vehicles,

said spaced grooves and upraised metal portions being elongated, ofuniform cross section throughout their length, and being alined in thedirection of travel of the railway vehicle wheels along the rails, andplastically deforming said upraised metal portions at least partiallyinto said spaced relieved areas by installing the frog member in a railcrossing in use by railway vehicles so that the vehicle wheels exertpressure upon said upraised portions to thus work harden the wearsurfaces.

References Cited in the tile of this patent UNlTED STATES PATENTS

